Torsional vibration damping device for motor vehicle clutch

ABSTRACT

A torsional vibration damping device ( 1 ), in particular for a motor vehicle clutch, said device comprising a disc ( 60 ) and a support ( 80 ) mounted mobile in rotation relative to each other about a common main axis, and linked in rotation via circumferential elastic members ( 90 ) damping torsional vibrations, said elastic members being interposed between the disc ( 60 ) and the support ( 80 ) and maintained in position circumferentially via lugs ( 65 ) of the disc ( 60 ) and lugs ( 82,84 ) of the support ( 80 ) whereon are supported the elastic members ( 90 ) and radially via a guide ring ( 100 ) passing through the elastic members ( 90 ) and integral with the disc ( 60 ). Said device is characterised in that the lugs ( 82,84 ) of the support ( 80 ) are mounted on either side of a section of the ring ( 100 ) and the lugs ( 65 ) of the disc ( 60 ) can move freely at the angle between the lugs ( 82,84 ) of the support ( 80 ).

The present invention relates to a torsional-vibration damping devicefor a motor-vehicle clutch, and in particular for a locking clutch of ahydrokinetic coupling apparatus.

A locking clutch (usually called “Lock-Up”) in the case of ahydrokinetic coupling apparatus acting between a drive element and adriven element for a motor vehicle, especially comprises a torsiondamper, an axially movable piston, at least one friction lining suitablefor being clamped between the said piston and a transverse wall integralwith the driven element.

The torsion damper includes an input part, an output part andcircumferentially-acting elastic members, for example springs,interposed between the said parts so as to couple them and absorb thevibrations.

In fact, it is known that a motor-vehicle engine operates in jerks(often imperceptible to the user) because of the very design of thethermodynamic cycle which occurs within the cylinders in order totransmit the power to the crankshaft. The torque on the engine shafttherefore follows a substantially sinusoidal curve corresponding to thealternate phases of pressure-release and of compression of the variouspistons in the cylinders. A phenomenon of vibration of the piecescoupled to the engine, either directly or indirectly, then ensues. Thistorsion damper makes it possible to limit the transmission of vibrationsgiven off by the engine, whether this is at standstill with the gearboxin neutral, or moving forward at low rotational speeds of the engine.

In the solutions of the prior art, springs are interposedcircumferentially between end stops carried by each of two input andoutput pieces. The torque is transmitted from one piece to the other byway of springs which are tasked with absorbing the jolts of thetransmission so that the driven shaft turns in a more uniform way. It isthus known to arrange these compression springs around a guide tubeforming a circumferential ring (inside guidance is then spoken of). Thepatents U.S. Pat. Nos. 1,334,537 and 5,411,439 describe such layouts.

However, these devices do not give complete satisfaction, especially byreason of the fact that the design of the end stops and their positionwith respect to the springs do not allow correct balancing of thestresses exerted on them as well as correct centring of the springs andthus correct damping of the vibrations.

Moreover, in all these devices, the springs are not all compressed atthe same time in one direction or the other. They are compressed ingroups, one group in one rotational direction, one group in the otherdirection. This results in a loss of effectiveness and above all verypoor management of the working volume of the device with respect to thedesired damping.

Furthermore, problems very often persist due to the high rotation of thepieces in motion and to the centrifugal force induced, which has atendency to off-centre the springs and to disturb their operation. It istherefore possible to improve the effectiveness of such devices.

One object of the present invention is therefore especially to solve atleast some of these problems by proposing a solution which is simple toimplement, compact, reliable and inexpensive.

To that end, the invention relates to a torsional-vibration dampingdevice, in particular for a motor-vehicle clutch, the said devicecomprising a web and a support which are mounted movable in rotationwith respect to one another about the same main axis, and are linked inrotation by way of elastic members for damping the torsional vibrations,the said elastic members being interposed between the web and thesupport and held in position, on the one hand circumferentially, by wayof claws of the web and of claws of the support on which the elasticmembers bear, and, and the other hand radially, by way of a guide ringpassing through the elastic members and integral with the web, thedevice being characterised in that the claws of the support are mountedon either side of a section of the guide ring, and in that the claws ofthe web can travel freely in angle between the claws of the support.

Hence, the guiding of the elastic members is carried out in a morebalanced way than in the prior art, consequently providing for betterabsorption of the torsional vibrations of the device.

Advantageously, the claws of the web and the claws of the support willbe of axial orientation, the claws of the support moreover being groupedinto pairs each forming a U.

In order to reduce the bulk of the device without any loss ofeffectiveness, each claw of the web will preferably lie within thediameter of the guide ring, without projecting radially from it.

In order to better distribute the load over the elastic members, eachclaw of the web will bear on two substantially diametrally oppositepoints of the extremities of the elastic members.

In a general way, the guide ring will locally exhibit areas where itsthickness will be reduced radially in order to define hollow housings,and each claw of the web will then be placed in an associated housing soas to bear against the extremities of the elastic members.

By way of example, the guide ring could be of substantially circularcross-section and be flattened locally so as to define the saidhousings.

According to another embodiment which, in particular, makes it possibleto lighten the device, the guide ring could be hollow and, in order toform the housings, be flattened locally onto itself, reversing itsconcavity so as to have a kidney-bean-shaped cross-section.

In order to reduce the friction between the ring and the guide members,in particular because of the centrifugal forces in play, the ring could,moreover, be flattened substantially opposite the housings and over itsentire periphery in order to exhibit two lines of contact with theelastic members.

Advantageously, the elastic members will be prestressed at rest betweentwo successive pairs of claws of the support, these claws then beingarranged, in this rest state, substantially opposite the claws of theweb.

According to one embodiment, the guide ring could be flattened locallyover its outer periphery so as to define the housings, and the outerclaw of each pair of claws of the support could then be arrangedradially beyond each claw of the web which is associated with it inorder to be able to pass above it while remaining in contact with theextremities of the elastic members when the web and the support turnwith respect to one another.

According to another embodiment, the guide ring could be flattenedlocally over its inner periphery so as to define the housings, and theinner claw of each pair of claws of the support could then be arrangedradially in front of each claw of the web which is associated with it,in order to be able to pass below it while remaining in contact with theextremities of the elastic members when the web and the support turnwith respect to one another.

So as to enhance the damping of the vibrations, the device couldcomprise a set of peripheral elastic members combined with a set ofcentral elastic members.

So as to provide variable damping as a function of the rotational speedof the pieces, the peripheral elastic members will preferably bearranged between the claws of the support and the claws of the web so asnot to operate in parallel with the central springs except when athreshold torque is reached between the support and the web.

The stiffness of the peripheral elastic members will preferably begreater than that of the central elastic members.

Advantageously, the width of the claws of the web which interact withthe first set of elastic members will lie within an angular sector whichis smaller than the angular sector in which lies the width of the clawsof the web which interact with the second set of elastic members.

In a general way, the width of the claws of the web could lie within anangular sector which is smaller than the angular sector in which liesthe width of the claws of the support, in such a way that, at rest,there is an angular clearance between the claws of the web and theextremities of the successive elastic members.

So as to enhance the centring of the elastic members and to betterdistribute the force with which they bear against the claws of thesupport, a protection washer could be is [sic] interposed between theextremities of each elastic member and the claws of the support.

The washer will preferably feature a shoulder projecting towards theinside of the elastic members.

In general, the claws of the web will be welded to the inside of thehousings of the guide ring.

In particular, the claws of the web will be equipped with innerroughnesses for welding them by electrical resistance welding into thesaid housings.

In general, the guide ring could feature a slot for putting it in placewithin the elastic members during assembly.

One of the claws of the web will preferably be welded straddling the twoextremities of the guide ring which are separated by the slot.

So as further to reduce the friction of the elastic members on the guidering, in particular when the elastic members are very long, provision ismade for at least one substantially cylindrical guide to be interposedlocally between the ring and each elastic member, preferably in acentral region thereof.

In order to be able to place this guide easily into the elastic member,while avoiding it being displaced along the ring, the guide will be madeof synthetic material and will feature radial bosses.

In particular, the bosses could be mounted elastically on the guide soas to facilitate their fitting within the elastic members, especiallywhen they are helical springs.

Advantageously, with the elastic members being helical springs, theturns of the extremities of the said springs could be shrunk and/or theturns of the extremities of the said springs could have a reducedwire-winding diameter.

According to another embodiment, the guide ring could be traversed byaxial orifices in which the claws of the web are mounted.

Other details, advantages and characteristics of the invention willemerge upon reading the description which follows, given by way ofexample with reference to the attached drawings, in which:

FIG. 1 is a sectional view of a first embodiment of atorsional-vibration damping device according to the invention,

FIG. 2 is an exploded view in perspective of FIG. 1,

FIG. 3 is another view in perspective, with partial cut away, of FIG. 1

FIG. 4 is a sectional view of an embodiment variant of FIGS. 1 to 3,

FIG. 5 is an exploded view in perspective of FIG. 4,

FIG. 6 is a sectional view of another embodiment of thetorsional-vibration damping device according to the invention,

FIG. 7 is an exploded view in perspective of FIG. 6,

FIG. 8 is another view in perspective, with partial cut away, of FIG. 7,

FIG. 9 is a sectional view of an embodiment variant of FIGS. 6 to 8,

FIG. 10 is an exploded view in perspective of FIG. 9,

FIG. 11 is another view in perspective with partial cut away of FIG. 9,

FIG. 12 is a view of a detail of the invention,

FIG. 13 is a view of a detail of an embodiment variant of FIG. 12,

FIG. 14 is a sectional view of a detail of another part of theinvention,

FIG. 15 is another sectional view of a detail of the invention,

FIG. 16 is another view of a detail of the invention,

FIG. 17 is another view of a detail of the invention,

FIG. 18 is a sectional view of another embodiment of the invention,

FIG. 19 is an exploded view in perspective of FIG. 18, and

FIG. 20 is a sectional view of an embodiment variant of FIGS. 18 and 19.

In FIG. 1 is represented a part of a hydrokinetic coupling device 1 fora motor-vehicle engine. This device 1 comprises, arranged in a leaktightbox 10 forming an oil sump, a torque converter 20 and a locking clutch.

This sump 10, here of metal, forms a drive element and is able to belinked in rotation about an axis xx′ to a drive shaft, namely to thecrankshaft (not represented) of an internal-combustion engine of themotor vehicle the transmission of which includes such a hydrokineticcoupling device.

The sump 10 is annular and composed of two half-shells face-to-face andfixed so as to be leaktight at their outer periphery, usually bywelding.

A first half-shell 11 is suitable for being linked in rotation to thedrive shaft and includes an annular wall 12 of overall transverseorientation extended by a cylindrical wall 13 of overall axialorientation.

The second half-shell, not represented for simplicity's sake in the sameway as the reaction disk of the hydrokinetic coupling device 1, isshaped so as to define an impeller disk with blades integral with theinner face of this half-shell. These blades face the blades 14 of aturbine disk 15 fixed by riveting or welding to a central hub 40internally featuring longitudinal splines for driving a driven shaft(not represented), namely the input shaft of the gearbox.

The hub 40 constitutes the output element of the locking clutch which isplaced axially between the transverse wall 12 and the turbine 15 of thetorque converter 20. The shaft is hollowed internally for forming achannel allowing oil to have access to a guide ring 44 implanted axiallybetween the hub 40 and the transverse wall 12.

The locking clutch also includes a piston 50 mounted sliding axiallyalong the annular outer periphery of a collar 46 of the guide ring 44,provided with a groove for fitting an annular seal, for example a gasket48.

This piston 50, carrying friction linings 70 (bonded, for example),delimits, with the ring 44 and the wall 12, a variable-volume chamber 45fed via the ring 44 featuring piercings 43 linked to the channel of theabove-mentioned driven shaft. The linings 70 are, needless to say,suitable for being clamped between the piston 50 and the transverse wall12 of the half-shell 11.

The locking clutch also comprises a web 60 installed at the outerperiphery of the piston 40 and featuring, at its outer periphery, andradially beyond the piston 40, straight-line claws 65 orientedsubstantially axially.

These claws 65 interact, as is described later, with a number of pairsof claws 82 and 84 of axial orientation of a support 80 arrangedcoaxially with the web 60 and movable in rotation with respect to it.Each pair of claws 82 and 84 of the support 80 forms a U, the opening ofwhich is directed towards the claws 65 of the web 60.

The pairs of claws 82 and 84 are carried by the turbine disk 15 whichcan thus act as a support, but they could be carried by a flangeintegral with the central hub 40 as is represented on other figures,especially all the perspective views.

Circumferentially-acting elastic members, such as springs 90, alsointeract with the straight-line claws 65 of the web 60 and the claws 82and 84 of the support 80 so as to link in rotation the web 60 and thesupport 80, while absorbing the torsional vibrations undergone by thedevice 1.

Hence, the claws 65 of the web and 82 and 84 of the support act as adrive means between the web and the support, and as abutment and supportmeans for the springs 90.

The axial orientation of the claws 625 of the web and of the claws 82and 84 of the support 80 may take any direction without modifying thecharacteristics of the invention. The claws could have anotherinclination, so as to resolve problems of bulk for example, thisorientation may especially be radial.

It will be noted, with the exception of the gasket 48, that the piecesof the hydrokinetic coupling device are of metal, usually of stampedsheet metal.

The locking clutch is completed by a torsion damper 35 installed, forthe most part, between the turbine disk 15 and the wall 12 of thehalf-shell 11. This damper 35 consists of an output part formed by thesupport 80, of an input part formed by the web 60, and ofcircumferentially-acting springs 90.

The springs 90, for example six in number, are mounted around a guidering 100 having a circular cross-section with axis 105 and preferablytaking the form of a hollow tube which is bent and closed over itself.In rest position, the extremities 90 a and 90 b of the springs 90 bear,with prestress or with clearance, against two successive pairs of claws82 and 84 of the support 80, and, as the case may be (depending onwhether there is or is not clearance) between two successive claws 65 ofthe web 60 (see FIG. 3).

When the web 60 and the support 80 turn with respect to one another(that is to say when the piston 50 turns with respect to the turbinedisk 15), the springs 90 are compressed between, on the one hand, a pairof claws 82 and 84 of the support 80 and, on the other hand, between aclaw 65 of the web 60, as can be seen in FIG. 3. It will be noted thatif the direction of rotation is reversed, the springs 90 always work incompression since they are compressed between another pair of claws 82and 84 of the support and another claw 65 of the web 60.

For that to be possible, provision is made for the claws 65 of the web60 to be able to be displaced circumferentially between the pairs ofclaws 82 and 84 of the support 80. This is possible because of the factthat each pair of claws 82 and 84 forms a U and that each peripherallyouter claw 82 of each pair of claws of the support 80 passes above (thatis to say beyond, peripherally speaking) the corresponding claw 65 ofthe web 60. In other words, the claws 65 of the web can be displacedcircumferentially between the pairs of claws 82 and 84, within theaperture of their U shape.

Furthermore, so as to avoid the straight-line claws 65 of the web 60projecting radially from the diameter of the guide ring 100, they arearranged in hollow housings 104 of the said ring 100, which arepreferably produced by flattening (see also FIGS. 12 and 13). Theflattening is such that the thickness E (the diameter in the presentcase) of the ring 100 is at least half, such that the claws 65 of theweb 60, for example welded to the guide ring 100 in the bottom of thehousings 104, can bear against the extremities 90 a and/or 90 b(depending on whether or not this is in the rest state) of the springs90 at two substantially diametrally opposite points 92 and 94 (FIG. 2).

As can be seen better in FIG. 3, each pair of claws 82 and 84 of thesupport 80 bears on either side of the straight-line claw 65(diagrammatically above and below), at two substantially diametrallyopposite lines 96 and 98 spaced away from the axis 95 of the springs 90.

Furthermore, when the web 60 and the support 80 are in rotation withrespect to one another (FIG. 3), the pairs of claws 82 and 84 of thesupport 80 and the claws 65 of the web 60 are offset in angle(positively or negatively depending on the direction of rotation). Theouter claw 82 of each U-shaped support can thus pass freely radiallybeyond the corresponding claw 65.

Thus, the bearing rest consisting of the claws 82 and 84 of the support80 and the claws 65 of the web 60 allows very good balancing of the loadapplied to the springs, which has the effect of not impairing thedamping of the torsional vibrations nor the power transmission when theclutch is operating. This also makes it possible to reduce the frictionof the springs 90 on the guide ring 100 by better distributing theforces onto the springs 90 so as to avoid them curving outwards orinwards, especially under the effect of centrifugal force.

In FIGS. 4 and 5, the structure is reversed in the sense that the web 60is fixed to the blades 14 of the disk 15 and the support 80 is fixed tothe flywheel 50. Furthermore, it will be noted that the guide ring 100is flattened internally in such a way that the inner claw 84 (thatsituated closest to the axis xx′ of the device) of each pair of claws 82and 84 of the support 80 can pass “below” each claw 65 of the web 60upon changes of the direction of rotation of the web with respect to thesupport. The claw 65 of the web is welded into the housing 104 withoutprojecting radially (this time internally) from this housing, and italso bears at two diametrally opposite points 92 and 94 of the springs90 (see FIG. 5).

Needless to say, this embodiment variant, in terms of the flattening ofthe guide ring 100, can be adapted to the solution of FIGS. 1 to 3, justlike the external flattening of the guide ring illustrated by FIGS. 1 to3 can be used in the embodiment of FIGS. 4 and 5. There are therefore 4possible combinations for these two embodiments which are a function ofthe respective position of the web and of the support and of the inneror outer location of the flattened areas 104 of the ring 100.

In FIGS. 6 to 8, a damper 35 similar to those of the preceding figurescan be seen represented, but in this damper there are two sets ofsprings arranged into two concentric circles.

First of all there is a first set, called peripheral set, including sixsprings 190 mounted between a first set of straight-line claws 165 ofthe web 60 and a first set of pairs of claws 185 of the support 80,these springs 190 needless to say being mounted and guided around afirst guide ring 100 integral with the web 60.

Furthermore there is a second set, called central set, also includingsix springs 290 mounted between a second set of straight-line claws 265of the web 60 and a second set of pairs of claws 285 of the support 80,these springs 290 needless to say being mounted and guided around asecond guide ring 200 also integral with the web 60 (FIG. 6). Needlessto say, once mounted (see FIG. 8), the springs 190 and 290, at rest, arealso prestressed between the pairs of claws 185 and 285 of the support80, which here is in two parts linked together, for example by rivets.

In the variant of FIGS. 9 to 11, the structure is reversed. The web 60is linked to the flywheel 50 and carries two sets of straight-line claws165 and 285 interacting with the two sets of pairs of claws 185 and 285of the support 80 mounted on the blades 15. The mounting of thistorsional-vibration damping device is similar to that of the precedingembodiment variant, that is to say that, at rest, the claws 165 and 265of the web are placed facing pairs of claws 185 and 285 of the support80, while bringing the extremities of each spring 190 and 290 to bearbetween two pairs of claws 185 and 285 of the support.

The operation of the two embodiment variants of FIGS. 6 to 8 and 9 to 11is special. Either the device operates with the addition of thestiffness of the two sets of springs 190 and 290, or it operates like adamper known as “double-slope damper”.

To do that, the damping device is designed in such a way that thesprings 190 and 290 do not work at the same time (in parallel) exceptwhen a certain torque threshold is reached. Below this threshold, onlythe inner springs 290 work in compression. Beyond this threshold, theaction of springs 190 comes to be added to that of the springs 290 so asto increase the stiffness and thus the restoring torque.

In order to achieve that, it is arranged that the claws 165 of the webwhich interact with the set of peripheral springs 190 have a width suchthat, when the web 60 turns a little with respect to the support 80, thesprings 290 are compressed as from the first angular offset between thepairs of claws 285 and the claws 265 of the web, but the claws 165 ofthe web do not yet come into abutment against the springs 190, in such away that they do not mechanically link the web to the washer. Once thetorque threshold has been exceeded, the springs 190 come into operationbetween the web and the support, bearing against the claws 165 of theweb 60.

In a variant, it is possible, needless to say, to arrange that it is theperipheral springs 190 which operate first, then the action of thecentral springs 290 comes to be added once the torque threshold has beenexceeded.

The stiffness of the two sets of springs 190 and 290 can also bedifferent so as to ensure a progression within the damping. The springsoperating first can thus be of a lesser stiffness than that of thesprings the action of which comes to be added once the threshold torquehas been exceeded.

It is also possible to provide for an angular clearance in each set ofsprings 190 or 290 (or 90 in the case of the preceding solutions with asingle group of springs) so that the damping of the torsional vibrationsdoes not really start until a certain angular offset exists between thesupport 80 and the web 60. That makes it possible to obtain anotherdamping of the dual-slope type, with a zero slope for low angularoffsets. To do that, provision is made for the claws 165, 265 (or 65) tofeature a width lying in a smaller angular sector than the angularsector in which the width of the corresponding pairs of claws 185, 285(or 82 and 84) of the support 80 lies. At rest, the springs in this casebear only against two consecutive pairs of claws of the support 80,without any contact with the claws of the web 60.

In FIG. 12, it is seen how the flattening of the guide ring 100 and 200,leading to the formation of the housings 104, can be carried out. Thisflattening is such that the thickness E of the ring is reduced by abouthalf so that the claw 65 (or 165 and 265), once welded (the welding isrepresented in the figure by a shaded area) into the housings 104, doesnot project (here externally) from it.

It is also seen how each claw 65 of the web can be displacedcircumferentially between the pairs of claws 82 and 84 of the support.

Finally, it is seen that a protection and support washer 110 has beeninterposed between the extremity of the springs 90 and each claw of thesupport and of the web. This washer 110, preferably made ofwear-resistant plastic, allows better support for the springs (morehomogeneous distribution of the load).

In FIG. 13, which is an embodiment variant of FIG. 12, it is seen thatthe washer 110 features a shoulder (or a skirt) 115 which is insertedbetween the turns of each spring 90. This has the effect of enhancingthe radial centring of the said springs, of better distributing thesupport for them on the claws of the support 80, and also of reducingthe friction between the springs and the guide ring 100.

In FIG. 14, a complementary solution is seen for reducing the wear onthe guide ring and the springs. This solution consists in flattening theguide ring 100 over its entire periphery (inner or outer, depending onthe positioning of the housings 104), substantially opposite thehousings 104, in such a way that the springs bear on two lines offriction 106 and 108 instead of a single one.

In FIG. 15, another solution is seen for producing the housings 104. Inthis case, the flattening of the guide ring (necessarily hollow here) issuch that its concavity is reversed on itself so as to give it akidney-bean shape or a flattened U-shape.

In FIG. 16, it is seen that the ring 100 and 200 is in reality formedwith a slot 102 facilitating the mounting of the springs. As it ispreferable not to leave it open, advantage is taken of the welding ofone of the claws 65 of the web so as to close the ring by welding thesaid straight-line claw straddling the two extremities 100 a and 100 bof the ring, covering over the slot 102. This avoids welding the twoextremities of the tube directly and deforming it.

Furthermore, it will be noted in this figure that each claw 65 of theweb 60 features bosses 68 (roughnesses) on the side where it is weldedinto the housing 104 of the ring. These bosses 68 serve for spot welding(or welding in parallel lines if these bosses are linear) the claw 65 ofthe web 60 by the passing of high-intensity current (resistancewelding). To that end, the claw 65 of the web 60 also features stampingrecesses 69, on the opposite side to the said bosses.

In FIG. 17 it is seen that an internal guide 120 is interposed betweeneach spring 90 and the guide ring 100. This takes the form of a sleevemade of plastic having an internal surface state allowing the spring toslide on the ring, so reducing the friction. This sleeve is preferablyplaced midway between the two extremities of each spring 90 so as reducethe overhang and thus any metal-against-metal friction. The sleevemoreover features annular external bosses 125 which make it possible tomount it by screwing within the spring 90, interacting, to that end,with the pitch of its turns. Moreover, once mounted on the ring, thissleeve 120 is blocked in translation and remains firmly in place thanksto these annular bosses 125. Likewise, several sleeves 120 can bemounted on the same spring.

It is also possible to provide for these bosses 125 to be mountedelastically so as to mount the sleeve 120 no longer by screwing it butby pushing it axially within the spring, the bosses 165 being retractedupon each passing of one turn of the spring.

In FIGS. 18 to 20, the clutch is of the type with a double frictionsurface. The piston 50 is integral with the half-shell 11 by way oftabs, as is known. The web 60 carries two sets of friction surfaces 70,one intended to come into contact with the transverse surface 12 of thehalf-shell 11, and the other intended to come into contact with thepiston 50, which comes to clamp the web 60 against the half-shell 11 fortransmitting the input torque. In this way, the transmissible torque ofthe clutch is doubled without any increase in its dimensions nor in theforces to be applied. Any one of the damping devices described in thepreceding figures can be adapted to this type of clutch.

As for FIGS. 1 to 5, four combinations are possible between the solutionof FIGS. 18–19 and the solution of FIG. 20, depending on the relativearrangement of the web 60 and of the support 80 and depending on theinner or outer positioning of the flattening 104 of the ring 100.

It should be clearly understood, however, that these examples are givenonly by way of illustration of the subject of the invention, of whichthey do not in any way constitute a limitation.

Thus the number of springs, and consequently the number of claws, mayvary.

The turns of the extremities of the springs may also be shrunk. Theextremity of the springs is an area where the springs have a tendency torub more on the guidance means. The shrunken turns have the advantage ofthus favouring wear of the springs in an area where the metal works witha low stress level.

In the same way, it may be beneficial to give the springs a barrelshape, with a reduced winding diameter at the extremities.

The invention may be applied to any other coupling mechanism, such as ahydrokinetic coupler, a dry clutch in an oil bath, a clutch with one ormore disks. It can be used in various fields of industry.

1. Torsional-vibration damping device (1), for a motor-vehicle clutch,the device comprising a web (60) and a support (80) which are mountedmovable in rotation with respect to one another about a main axis, andare linked in rotation by way of circumferential elastic members (90;190, 290) for damping the torsional vibrations, the elastic membersbeing interposed between the web (60) and the support (80) and held inposition, on the one hand circumferentially, by way of claws (65; 165,265) of the web (60) and of claws (82, 84; 185, 285) of the support (80)on which the elastic members (90; 190, 290) bear, and, on the other handradially, by way of a guide ring (100; 200) passing through the elasticmembers (90; 190, 290) and integral with the web (60), wherein the claws(82, 84; 185, 285) of the support (80) are mounted on either side of asection of the ring (100), and wherein the claws (65; 165, 265) of theweb (60) being freely movable to an angle between the claws (82, 84;185, 285) of the support (80), wherein the claws (65; 165, 265) of theweb (60) and the claws (82, 84; 185, 285) of the support (80) beingoriented substantially in the direction of the main axis, and whereinthe claws of the support being grouped into pairs each forming a U, andwherein at least one substantially cylindrical guide (120) is mountedwithin only one of the elastic members (90; 190, 290) and is interposedradially between the guide ring (100; 200) and the one of the elasticmembers (90; 190, 290) to which the at least one substantiallycylindrical guide (120) is mounted along a circumferential length of theone of the elastic members (90; 190; 290) and between the ends thereof,and wherein the guide ring (100; 200) locally exhibits areas where itsthickness (E) is reduced radially in order to define hollow housings(104), and in that each claw (65; 165, 265) of the web (60) is placed inan associated housing (104) so as to bear against the extremities (90 a,90 b) of the elastic members (90; 190, 290).
 2. Device (1) according toclaim 1, wherein each claw (65; 165, 265) of the web (60) lies withinthe diameter of the guide ring (100, 200), without projecting radiallyfrom it.
 3. Device (1) according to claim 1, wherein each claw (65; 165,265) of the web (60) bears on two substantially diametrically oppositepoints (92, 94) of the extremities (90 a, 90 b) of the elastic members(90; 190, 290).
 4. Device (1) according to claim 3, wherein the guidering (100; 200) is flattened locally over its inner periphery so as todefine the housings (104), and in that the inner claw (84) of each pairof claws of the support is arranged radially in front of each claw (65;165, 265) of the web (60) which is associated with it, in order to beable to pass below it while remaining in contact with the extremities(90 a, 90 b) of the elastic members (90; 190, 290) when the web (60) andthe support (80) turn with respect to one another.
 5. Device (1)according to claim 1, wherein the guide ring (100; 200) is ofsubstantially circular cross-section and is flattened locally radiallyso as to define the housings (104).
 6. Device (1) according to claim 1,wherein the guide ring (100; 200) is hollow and, in order to form thehousings (104), is flattened locally onto itself.
 7. Device (1)according to claim 1, wherein the guide ring (100; 200) features a flaton the inner radial side of its entire periphery in order to exhibit twolines of contact (106, 108) with the elastic members (90; 190, 290). 8.Device (1) according to claim 1, wherein, at rest, the elastic members(90; 190, 290) are prestressed between two successive pairs of claws(82, 84; 185, 285) of the support (80), these claws then being arranged,in this rest state, substantially opposite the claws (65; 165, 265) ofthe web.
 9. Device (1) according to claim 1, further comprising a set ofperipheral elastic members (190) combined with a set of central elasticmembers (290).
 10. Device (1) according to claim 9, wherein theperipheral elastic members (190) are arranged between the claws (82, 84;185, 285) of the support (80) and the claws (65; 165, 265) of the web(60) so as not to operate in parallel with the central elastic members(290) except when a threshold torque is reached between the support (80)and the web (60).
 11. Device (1) according to claim 9, wherein thestiffness of the elastic members (190) is greater than that of thecentral elastic members (290).
 12. Device according to claim 9, whereinthe width of the claws (165) of the web (60) which interact with thefirst set of elastic members (190) lies within an angular sector whichis smaller than the angular sector in which lies the width of the claws(265) of the web (60) which interact with the second set of elasticmembers (290).
 13. Device (1) according to claim 1, wherein the width ofthe claws (65; 165, 265) of the web (60) lies within an angular sector(α_(W)) which is smaller than a second angular sector (α_(S)) which liesthe width of the claws (82, 84; 185, 285) of the support (80), in such away that, at rest, there is an angular clearance (α_(C)) between theclaws (65; 165, 265) of the web (60) and the extremities of thesuccessive elastic members (90; 190, 290).
 14. Device (1) according toclaim 1, wherein a protection washer (110) is interposed between theextremities (90 a, 90 b) of each elastic member (90; 190, 290) and theclaws (82, 84; 185, 285) of the support (80).
 15. Device (1) accordingto claim 14, wherein the washer (110) features a shoulder (115)projecting towards the inside of the elastic members (90; 190, 290). 16.Device (1) according to claim 1, wherein the claws (65; 165, 265) of theweb (60) are welded to the inside of the housings (104) of the guidering (100; 200).
 17. Device (1) according to claim 16, wherein the claws(65; 165, 265) of the web (60) are equipped with inner roughnesses (68)for welding them by electrical resistance welding into the housings(104) of the guide ring (100; 200).
 18. Device (1) according to claim17, wherein one of the claws (65; 165, 265) of the web (60) is weldedstraddling the two extremities of the guide ring (100; 200) which areseparated by the slot (102).
 19. Device (1) according to claim 1,wherein the guide ring (100; 200) features a slot (102) for putting itin place within the elastic members (90; 190, 290) during assembly. 20.Device (1) according to claim 1, characterised in that wherein the guide(120) is made of synthetic material and features radial bosses. 21.Device (1) according to claim 20, wherein the bosses (125) are mountedelastically on the guide (120).
 22. Device (1) according to claim 1,wherein, with the elastic members (90; 190, 290) being helical springs,the turns of the extremities of the springs (90; 190, 290) are moretightened compared to other turns.
 23. Device (1) according to claim 1,wherein, with the elastic members (90; 190, 290) being helical springs,the turns of the extremities of the springs (90; 190, 290) have areduced wire-winding diameter compared to other turns. 24.Torsional-vibration damping device (1) for a motor-vehicle clutch, thedevice comprising a web (60) and a support (80) which are mountedmovable in rotation with respect to one another about a main axis, andare linked in rotation by way of circumferential elastic members (90;190, 290) for damping the torsional vibrations, the elastic membersbeing interposed between the web (60) and the support (80) and held inposition, on the one hand circumferentially, by way of claws (65; 165,265) of the web (60) and of claws (82, 84: 185, 285) of the support (80)on which the elastic members (90; 190, 290) bear, and, on the other handradially, by way of a guide ring (100; 200) passing through the elasticmembers (90; 190, 290) and integral with the web (60), wherein the claws(82, 84; 185, 285) of the support (80) are mounted on either side of asection of the ring (100), and wherein the claws (65: 165, 265) of theweb (60) being freely movable to an angle between the claws (82, 84;185, 285) of the support (80), wherein the claws (65; 165, 265) of theweb (60) and the claws (82, 84; 185, 285) of the support (80) beingoriented substantially in the direction of the main axis, and whereinthe claws of the support being grouped into pairs each forming a U,wherein at least one substantially cylindrical guide (120) is mountedwithin only one of the elastic members (90; 190, 290) and is interposedradially between the guide ring (100; 200) and the one of the elasticmembers (90; 190, 290) to which the at least one substantiallycylindrical guide (120) is mounted along a circumferential length of theone of the elastic members (90; 190; 290) and between the ends thereof,wherein each claw (65; 165, 265) of the web (60) bears on twosubstantially diametrically opposite points (92, 94) of the extremities(90 a, 90 b) of the elastic members (90; 190, 290), and wherein theguide ring (100; 200) is flattened locally radially over its outerperiphery so as to define the housings (104), and wherein an outer claw(82) of each pair of claws of the support (80) is arranged radiallybeyond each claw (65; 165, 265) of the web (60) which is associated withit in order to be able to pass above it while remaining in contact withthe extremities (90 a, 90 b) of the elastic members (90; 190, 290) whenthe web (60) and the support (80) turn with respect to one another. 25.Torsional-vibration damping device (1) for a motor-vehicle clutch, thedevice comprising a web (60) and a support (80) which are mountedmovable in rotation with respect to one another about a main axis, andare linked in rotation by way of circumferential elastic members (90;190, 290) for damping the torsional vibrations, the elastic membersbeing interposed between the web (60) and the support (80) and held inposition, on the one hand circumferentially, by way of claws (65: 165,265) of the web (60) and of claws (82, 84; 185, 285) of the support (80)on which the elastic members (90; 190, 290) bear, and, on the other handradially, by way of a guide ring (100; 200) passing through the elasticmembers (90; 190, 290) and integral with the web (60), wherein the claws(82, 84; 185, 285) of the support (80) are mounted on either side of asection of the ring (100), and wherein the claws (65: 165, 265) of theweb (60) being freely movable to an angle between the claws (82, 84;185, 285) of the support (80), wherein the claws (65: 165, 265) of theweb (60) and the claws (82, 84; 185, 285) of the support (80) beingoriented substantially in the direction of the main axis, and whereinthe claws of the support being grouped into pairs each forming a U,wherein at least one substantially cylindrical guide (120) is mountedwithin only one of the elastic members (90; 190, 290) and is interposedradially between the guide ring (100; 200) and the one of the elasticmembers (90; 190, 290) to which the at least one substantiallycylindrical guide (120) is mounted along a circumferential length of theone of the elastic members (90; 190; 290) and between the ends thereof,and wherein the guide ring (100; 200) is traversed by axial orifices inwhich the claws (65; 165, 265) of the web (60) are mounted.